This invention generally relates to a light for illuminating a task area, more particularly to a light which illuminates a task area by using indirect lighting which addresses eye strain concerns. The light is especially suitable to be mounted onto or positioned within the casing of a monitor of computer equipment with the objective of substantially reducing glare onto the display screen of the monitor, typically while providing beneficial indirect lighting for the task area being illuminated.
In the past, task lighting devices of various types have been provided or proposed for lighting task areas, while being directed toward reducing reflected glare. Some of them are intended to provide direct illumination of computer monitor display screens. For example, U.S. Pat. No. 5,722,754 attempts to ease eye strain by providing auxiliary lighting of a computer monitor display screen by illuminating it with simulated natural daylight from full spectrum bulbs. The display screen is intentionally and directly illuminated by the full spectrum illumination source.
Another type of task lighting is illustrated in U.S. Pat. No. 5,655,833, which provides a slidably mounted lighting fixture secured to the side panel of a computer monitor. This lighting fixture is designed to provide work surface illumination on a surface adjacent to a computer monitor and without unnecessarily increasing ambient room lighting. Another approach is proposed by U.S. Pat. No. 5,530,628, which shows a task light for use with office furniture systems having a backwall which is illuminated by the task light.
Task lighting fixtures of these general types light a task area or a monitor display. They do not concentrate upon lighting a task area which is in front of a display screen such as that of a computer monitor. None suggest the use of indirect lighting to achieve this type of task lighting. Relatively recent studies and observations have recognized a condition which has come to be known as Computer Vision Syndrome (or CVS), which is a repetitive stress injury, believed to be caused by the act of refocusing on a computer screen image again and again. Most users of computer monitors or other equipment incorporating self-illuminating display screens and the like are susceptible to suffering eyestrain. Symptoms of CVS include headaches, blurred vision and dry eyes.
CVS development typically is associated with decreasing of the blink reflex. Blinking can be reduced to an unnatural frequency when one stares into a computer monitor. An average person blinks twenty-two times per minute. During reading sharp black letters on white background, the rate decreases to twelve times per minute. At the computer, the blink reflex rate is reduced to only four times per minute. Such reduced blinking increases tear evaporation, resulting in a substantial increase in the exposure of the corneas. The result is dryer, more irritated eyes.
Unlike printed type which presents sharp edges in order to accurately interpret and maintain focus, users of display screens and computer monitors must focus and refocus involuntarily in an attempt to keep the images sharp. This is due in large part to the fact that display screens comprise pixels (minute subdivisions) which are very difficult for the human eye to keep in focus. Repetitive stress of the eye muscles results as the plane of focus drifts out to a resting point of accommodation. It is presently believed that this accommodation phenomenon is instrumental in the decreased blinking rate associated with computer use.
Glare from and at the workspace is a significant contributor to CVS. Ambient light which falls across a display screen has a lightening effect, decreasing contrast sharpness. Because of this uniform glare, eyes are strained in order to see and discern the characters appearing on the display screen. Another aspect of reflective glare involves objects which can be seen on the screen in addition to the screen image. So-called veiling reflections require the eyes to continuously filter out the reflected image from the screen image. On the whole, reflective glare is generated by light sources outside of the screen, such as behind, above or next to the operator. Needless illumination is bounced onto the monitor, and the light from these unexpected sources enhances the likelihood that CVS will result.
It has been determined that eye strain generally associated with CVs, and the associated symptoms such as burning or tired eyes, blurred vision, loss of focus and headaches, can be significantly reduced by systems of the present invention which incorporate indirect lighting for illuminating a task area. When properly utilized, indirect lighting minimizes both direct glare and reflective glare on the video display tube. Uniform glare and veiling reflections issues are significantly controlled. By reducing the external illumination of the display screen while still adequately lighting the task area, eye strain symptoms are reduced, and blinking frequency rates are more naturally increased.